When Derek and Burger are arguing, Vic's painting is already ripped. In the next shot, just before Derek throws a mug through it, the painting is back to normal.
In the flashback scene in which Vic was shown to hate the fact that Iron Weasel fought all of the time, the band was seen in the same clothes that they wear in the present day and with the same physical appearance that they have in the present day. In order for the scene to have truly been a flashback, it would have had to have occurred over seven years ago (when the band was at the height of its popularity), meaning that the band would have, in all likelihood, looked and dressed differently.